mattermost

name	mattermost
description	Read, search, and act in Mattermost via the `mm` CLI. Use whenever the user mentions Mattermost, chat messages, team chat, unreads, DMs, channel history, mentions, threads, or wants to catch up, post a message, react to something, set their status, pin/edit/delete a post, or run any other chat action from the terminal. The CLI outputs agent-friendly JSON by default with thread IDs, bot detection, reactions, and channel refs - no parsing needed.
allowed-tools	Bash, Read, Write, Edit, Glob, Grep, AskUserQuestion

Mattermost CLI (mm)

Read and write in Mattermost from the command line. Single static Go binary, JSON output by default for agents, --human for markdown.

Setup

Check if mm is already on PATH and authenticated:

mm whoami

If that works, jump to Start here.

If mm is missing, install it. Homebrew is the canonical path:

brew install ayusavin/tap/mm

Alternatives if Homebrew isn't available:

# Go toolchain
go install github.com/ayusavin/mattermost-cli/cmd/mm@latest

# Or grab a prebuilt binary
# https://github.com/ayusavin/mattermost-cli/releases

Note: the old PyPI package mattermost-cli is dead. Do not install it.

Then authenticate once with a Personal Access Token (Profile > Security > Personal Access Tokens in Mattermost):

mm login --url https://chat.example.com --token YOUR_PAT
mm whoami   # verify

Password + MFA fallback:

mm login --url https://chat.example.com --login [e-mail] --mfa 123456

MATTERMOST_URL / MATTERMOST_TOKEN / MATTERMOST_TEAM env vars override the on-disk config (~/.config/mm/config.json, mode 0600). See references/setup.md for multi-server tricks and troubleshooting.

Start here: mm overview

Always run this first. One call returns everything you need to triage:

mm overview              # last 6 hours (default)
mm overview --since 1d   # last 24 hours

Response sections:

• mentions — posts that @-mention you, including root context for replies
• unread — channels with unread counts
• active_channels — channels with recent posts, sorted by recency

Every channel entry carries a ref field you pass straight into mm messages. Never reconstruct refs by hand — use what mm gives you.

Fast local reads: sync daemon + mm query

For heavy reading, run the sync daemon once. It mirrors your Mattermost (channels, members, posts, reactions, read state) into a local SQLite cache and keeps it live over the WebSocket. Then query that cache with SQL: instant, no per-command network round-trip, no cold start.

mm sync start     # backfills, then realtime-syncs in the background
mm sync status    # {running, ipc_reachable, ws_connected, backfill_done, ...}
mm sync stop
mm sync logs

Once backfill_done is true, query the cache (read-only SQL → JSON rows, like Notion's query-database):

mm query --schema                                  # discover tables + views
mm query "SELECT name, display_name, unread_count, mention_count
          FROM v_unread ORDER BY unread_count DESC LIMIT 20"
mm query "SELECT author, message, created_at FROM v_post
          WHERE channel_id='<id>' AND delete_at=0
          ORDER BY create_at DESC LIMIT 30"
mm query "SELECT display_name, type, team FROM v_channel
          WHERE lower(name) LIKE '%deploy%'"        # one query, not a loop
mm query "SELECT * FROM sync_state"                 # freshness / liveness

Enriched views mirror the post/channel JSON shapes:

• v_post — id, thread_id, is_reply, author, message, created_at, channel, team, file_count, reply_count, is_bot, bot_name, reactions (JSON), files (JSON).
• v_channel — channels + team + resolved display_name.
• v_unread — unread_count, mention_count per channel.
• v_thread — posts grouped by thread.
• Full-text search via FTS5: SELECT p.* FROM posts p JOIN posts_fts f ON p.rowid=f.rowid WHERE posts_fts MATCH 'deploy'.

mm query is read-only (SELECT / WITH / EXPLAIN only). Writes still go through the normal commands (mm post/reply/dm/edit), which hand the result to the daemon so a follow-up mm query sees it immediately (read-your-writes). When the daemon is running and fresh, find-channel and other reads use the cache automatically; otherwise they fall back to the live API. MM_NO_DAEMON=1 forces the live path.

Don't loop or over-fetch. One mm query SELECT replaces the classic anti-patterns that make sessions slow:

• looping find-channel over guessed names → ... WHERE lower(name) LIKE '%x%'
• escalating --since (6h → 1d → 30d → all) → WHERE create_at > <epoch_ms>
• piping output to grep/python to filter or aggregate → do it in SQL

Process new messages: mm new / mm seen

mm new lists posts you haven't processed yet — newer than your cursor, across all channels, excluding your own posts. Decoupled from Mattermost read/unread: querying never marks anything read, and the cursor is your processing watermark, not a server flag. After reviewing, mm seen advances it to now.

mm new                 # posts since your cursor (run `mm seen` once to set a baseline)
mm new --since 1d      # don't look back further than 1d
mm seen                # record "processed through now"

Load older history: mm history

Backfill keeps only a recent window per channel (sized to cover unread). To pull deeper history into the cache so mm query / mm messages see it locally:

mm history <channel> --limit 500

Reading deeper than the window without mm history still works — mm messages falls back to the live API — it just isn't cached.

Reading

mm messages <ref>                # last 30 messages, chronological
mm messages <ref> --since 2h
mm messages <ref> --threads      # group by thread (root + reply count + last)
mm messages @username            # DM with someone
mm thread <thread_id>            # root + last 9 replies
mm thread <thread_id> --limit 0  # entire thread
mm mentions --since 3d
mm search "from:alice deploy after:2025-01-01"
mm find-channel <term>           # search your teams' channels by name/purpose
mm find-channel <term> --type public
mm search-user <term>            # users by username, full name, nickname, email
mm channel <ref>                 # purpose, header, member/pinned counts
mm channels --type dm --since 6h
mm pinned <ref>
mm members <ref>
mm user @someone
mm download <file-id>            # save attachment to cwd; --output -, --force
mm watch                         # follow the WebSocket event stream

<ref> accepts a channel name (off-topic), @username for DMs, a ~name form, or a raw channel ID (use this for group DMs from overview output).

Acting (write commands)

mm post <ref> -m "deploy started"          # plain text
echo "long body" | mm post <ref> --read    # body from stdin
mm reply <post_id> -m "ack"                # threaded reply
mm dm @alice -m "ping"                     # direct message

mm react   <post_id> :white_check_mark:
mm unreact <post_id> :white_check_mark:

mm pin   <post_id>
mm unpin <post_id>

mm edit   <post_id> -m "fixed typo"        # only own posts
mm delete <post_id> --yes                  # only own posts; --yes is required

mm mark-read <ref>                         # clear unread badge

mm create-channel <name> --type public      # new channel (--type public|private)
mm create-channel <name> --team eng --purpose "..." --header "..."
mm add-user <ref> @username                 # add a user to a channel
mm join <channel>                           # join a public channel yourself

mm status away
mm status online -m "back at it" --emoji :coffee:
mm status --clear                          # remove custom status

<post_id> is the id field of any post you've already seen, or a full permalink — mm extracts the ID either way. <ref> and <post_id> are both accepted from previous JSON output without transformation.

Write commands return the created/updated resource as JSON so you can chain (e.g. take the id from mm post and feed it into mm pin).

Key JSON fields on posts

Field	What it's for
id	The post ID — pass to thread, reply, react, pin, edit, delete
thread_id	Pass to mm thread to read the full conversation
ref	On channel entries; pass to mm messages
is_bot / bot_name	Webhook and bot posts are flagged automatically
root	On reply-mentions; the original message being replied to
is_reply / reply_count	Thread structure
reactions	Emoji counts like {":+1:": 3, ":white_check_mark:": 1}
created_at	ISO 8601 UTC
file_count / files[]	Attachments. Each entry has id, name, size, mime_type, extension, and width/height for images. Pass id to mm download.

Bot posts from webhooks have alert content extracted from Slack-format attachments, so you see actual alert text, not empty messages.

Exit codes

Code	Meaning
0	OK
1	Generic error
2	Auth expired or invalid — run mm login again
3	Rate limited by the server — back off and retry

Always check the exit code before assuming a write succeeded.

Agent etiquette

• Read before you write. Run mm overview or mm messages <ref> first so you have correct ref/id/thread_id values.
• Prefer mm query for discovery and bulk reads when a sync daemon is running (check mm sync status). One SQL SELECT beats looping find-channel over guessed names or re-fetching with an ever-wider --since.
• Reply, don't post a new thread, when continuing an existing conversation. Use the thread_id from a previous post with mm reply.
• Confirm destructive ops with the user. mm delete requires --yes; don't supply it without explicit instruction.
• Don't spam reactions or messages on retries. If a write command's exit code is non-zero, check whether it actually went through (e.g. re-fetch the channel) before re-running.
• Always inspect attachments. A post text alone is often not the full message — screenshots, logs, PDFs, and design files carry the actual context. Whenever a post has file_count > 0, pull each entry from files[] with mm download <id> and open it (image viewer for screenshots, read for text/logs, pass to the appropriate tool for other formats) before responding or summarizing. Treating a post as understood without looking at its attachments is a frequent failure mode.

Further reading

• references/setup.md — install, auth, env vars, troubleshooting
• references/commands.md — full flag-level reference for every command
• references/scenarios.md — "what did I miss?", "summarize this channel", "is this resolved?"
• references/workflows.md — multi-step recipes: morning triage, incident reply, channel discovery